A technology for supporting driving of an automobile has been proposed in which an image including information effective for supporting driving is projected and drawn on a road surface so that a driver may drive the automobile by visually recognizing the image. Japanese Patent Laid-Open Publication No. 2010-26759 discloses a technology of detecting a lane on which an own vehicle is travelling, and determining whether the own vehicle deviates from the detected lane. When there is a risk of deviation from the lane, information or an image for alerting the deviation from the lane is projected and displayed on the road surface ahead of the own vehicle. Japanese Patent Laid-Open Publication No. 2011-207349 discloses a technology of recognizing a vehicle speed suitable for an own vehicle based on information on a road on which the own vehicle is travelling, and travelling information such as, for example, a speed of the own vehicle. When it is determined that it is preferable to slow down the own vehicle, light distribution of a head lamp is controlled such that visibility at a far front area of the own vehicle is reduced.